The invention relates to a test apparatus for testing a first and/or a second electrical machine, said test apparatus comprising: a torque transmitter for transmitting a torque between a first electrical machine and a second electrical machine, wherein the torque transmitter has a torque connection for the first electrical machine and a torque connection for the second electrical machine; an electrical shaft which has a first electrical connection for the first electrical machine and a second electrical connection for the second electrical machine. The synchronous generator (SG) to be tested and/or the gear unit to be tested can also be termed the ‘device under test’ (DUT). ‘Torque transmitter’ is here to be understood as meaning a device by means of which a torque can be transmitted. A torque transmitter can comprise, for example, a gear unit, a clutch, a shaft, a lever or some other device (in particular a mechanical, electromechanical or hydromechanical device) by means of which a torque can be transmitted. Another torque transmitter (in particular a gear unit under test) can be a to-be-tested part of the first and/or the second electrical machine. The gear unit of the first mentioned and/or of the other torque transmitter can be e.g. part of a hybrid drive system (HDS) in each case.
The invention also relates to a method for testing a first and/or a second electrical machine, comprising the following steps: supplying electrical power from an external power source to the first electrical machine for conversion of the supplied electrical power into mechanical power and/or supplying mechanical power to the first electrical machine; transmitting mechanical power from the first electrical machine to the second electrical machine; converting at least some of the mechanical power supplied to the second electrical machine into electrical power by means of the second electrical machine; transmitting to the first electrical machine, via an electrical shaft, at least some of the electrical power that was generated by the second electrical machine by means of the conversion of mechanical power; and converting at least some of the electrical power that was supplied to the first electrical machine by the second electrical machine into mechanical power by means of the first electrical machine.
DE 199 18 820 B4 describes a test rig for testing drive components. A first controller checks a power flow to a first electric motor used as a first torque generator. A second controller checks a power flow to a second electric motor used as a second torque generator. Both controllers are supplied from an AC line.
This known test apparatus is characterized by a high electrical power consumption during operation. This results in high energy costs and high acquisition and operating costs for the controllers.